1. Field of the Invention
The present invention relates to mechanical devices used for mounting a printed circuit board (PCB) into an appropriate receptacle. More particularly, it concerns levered mechanisms for use in inserting a PCB into a socket or receptacle to effect an electrical interface, maintaining the PCB in the fully engaged position during use and removing the PCB from the socket or receptacle.
2. Description of the Prior Art
Printed circuit boards are typically inserted manually or with the assistance of a mechanical device into a receptacle or socket for making an electrical connection between the PCB and the socket. The socket is mounted within a housing or structural frame which forms part of an overall unit. In a typical pin and socket PCB, a plurality of electrical contacts or pins are positioned in a connector which is mounted on the PCB adjacent the front edge thereof. The PCB is inserted into the socket by sliding the electrical contacts of the connector mounted on the PCB into an elongated opening in the socket until the electrical contacts are fully seated. When the PCB is properly inserted into the socket, electrical contact is established between the plurality of contacts of the connector on the PCB and the socket.
Various mechanical levered devices are available for assisting in properly inserting a PCB into the socket when manual insertion is not feasible. One such known mechanical levered device is pivotally mounted on or near the rear edge of a PCB and applies a leverage force against part of the housing or frame to aid in forcing the PCB connector into the elongated opening of the socket. This mechanical levered device merely pushes the connector into the socket until the lever action stops. The linear travel of the connector is always the same and is fixed by the mechanical device itself.
All PCB's, connectors, sockets and other structural features are manufactured within certain tolerances. In addition, the electrical contacts or pins of the connector are very short. During PCB installation, mating electrical surfaces between the connector and the socket must slide over each other for a certain linear distance in order to remove oxides and contaminants for good electrical conductivity. In practice the cumulative sum of the various tolerances and the relatively short length of the electrical contacts require precise alignment between the connector and the socket in order to effect and maintain electrical conduction.
The cumulative tolerances are frequently sufficient in magnitude to exceed the maximum linear distance that the mechanical levered device can move the PCB. If the cumulative tolerances exceed this maximum linear distance, then the relative position of the electrical contacts of the connector within the socket is sufficiently altered to result in no electrical contact or a poor electrical connection when the PCB is inserted with the aid of a mechanical levered device.
In addition, under these circumstances, when the PCB connector is inserted into a socket, even if initial electrical contact is established, any vibration or movement of the overall device tends to cause separation between the PCB connector contacts and the socket with the resulting loss of electrical conductivity.